Examine source code of Salesforce API Fieldnames

{
  "name": "Salesforce API Fieldnames",
  "version": "0.1.7resigned1",
  "manifest_version": 2,
  "description": "Extension shows the API field names on detail pages",
  "icons": {
    "16": "images/icon16__c.png",
    "128": "images/icon128__c.png"
  },
  "default_locale": "en",
  "background": {
    "scripts": [
      "scripts/background.js"
    ]
  },
  "browser_action": {
    "default_icon": {
      "19": "images/iconOff19__c.png",
      "38": "images/iconOff__c.png"
    },
    "default_title": "apinames"
  },
  "content_scripts": [
    {
      "matches": [
        "https://*.force.com/*",
        "https://*.salesforce.com/*"
      ],
      "js": [
        "scripts/contentscript.js"
      ],
      "run_at": "document_end",
      "all_frames": false
    }
  ],
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "{4937bac1-9ed8-4799-ab46-5377ab9c01fe}"
    }
  }
}